SCS Engineers
Fitchburg’s community center on the right (city hall is on the…
28 of 32 recommendations implemented
The energy use intensity (EUI) metric normalizes energy consumption by square footage so multiple buildings can be compared. The higher the EUI, the more energy a building uses per square foot during a year.
The chart above shows that all three were already performing better than buildings of similar type, census region, and climate zone. Data on the other buildings is from the Commercial Buildings Energy Consumption Survey prepared by the U.S. Energy Department’s Energy Information Administration, a widely used and publicly available benchmark reference.
At the time of the RCx, city hall’s EUI was 88,000 BTU/square feet. At 55,000 BTU/square feet the community center’s was even better.
More Information
The State and Local Energy Efficiency Action Network (SEE Action) helps states, utilities, and other local stakeholders take energy efficiency to scale and achieve cost-effective energy by 2020. The five-page Retro-Commissioning for State and Local Governments fact sheet is an excellent free resource.
However, thanks to geothermal heating and cooling, the library had the lowest EUI at 41,000 BTU/square feet In addition to lowering energy use, the system was installed to make it easier for the library to become a net zero energy building once solar panels are installed. At the time it was built in 2010, the city could only afford the necessary roof supports and other allowances.
The evaluation produced 32 recommendations. They’re estimated to cost $48,400 to implement and expected to save $22,660 annually.
Community Center
Estimated one-time implementation cost: $35,100
Estimated annual savings: $6,010
City Hall
Estimated one-time implementation cost: $7,400
Estimated annual savings: $5,900
Library
Estimated one-time implementation cost: $5,900
Estimated annual savings: $10,750
As of October 2015, the city had implemented 28. All three buildings will benefit from:
- Reprograming the air-handling unit with minimum and maximum flow controls and lowering the terminal unit’s maximum discharge temperature to 90° F
- Reducing outdoor air in air-handling units based on carbon dioxide concentrations and occupancy schedules.
The final four recommendations are proposed in the city’s 2016 budget.
For city hall, they’re implementing standby CFM (cubic feet per minute) setpoints in less frequently used areas and installing VFD (variable frequency drive) controls on cooling tower fans.
The final recommendations for the library are adding temperature resets to the air-handling unit and reducing the VFD minimum setting.
Even if they’re not approved, the city’s sustainable energy-use plan is reaping financial benefits no matter how extreme weather conditions are now and in the future.
Certified by the Association of Energy Engineers, Sam Cooke is manager of SCS Engineers’ Energy Management Group. E-mail scooke@scsengineers.com.
